Yes, a dual 2 ohm if wired in series equals 4 ohms. Of these two choices, the 10w3 would work best for you. A dual 6 ohm if wired in parallel is equal to 3 ohms and your amp is only stable down to 4 ohms, so this is too low. The only way the 10w6 would work with your amp is if you didn't bridge it and used 2 channels to power the 2 voice coils. You would lose a lot of power by doing it this way though so this isn't a very good option.

Are you stuck on JL. I have an infinity perfect 10 and it is the best sound quality sub I have ever heard. It is extremely tight sounding and punchy. And it will also get loud if you want it to. I got it new off of ebay for about 130 and love it. They have a single 4 ohm coil and would work great with your amp. I promise you wouldn't be dissapointed if you got one.